The overall goal of Core 9002, Scientific Services, is to provide shared scientific services for the individual scientific Projects. This Core Component is essential to the overall success of the Program Project. It makes five important contributions: First, by combining resources, it provides an economy of scale. Second, by providing well maintained facilities, it saves time and makes each Program Member more efficient. Third, by supporting trained technical support staff, it provides technical expertise, which is of particular benefit to new Program Members, especially young Project Leaders. Fourth, by providing quality control of shared reagents, the success rate of experiments is higher and the results of members in different Projects can more easily be directly compared. An, fifth, shared facilities facilitate the exchange of experimental ideas, methodology, and results, and limits the recurrence of experimental problems. Every Project in this Program Project benefits from the Scientific Services Core Component. The Core Component provides: 1) Cellculture and virus production facilities. 2) Microscropy facility. 3) Monoclonal antibody services. 4) major items of shared equipment. 5) General scientific support.